My understanding of self-mutilation/cutting is that it's done by the student to gain 'control' over themselves/environment. I suppose it would be related to the same forces that result in eating disorders.
I've search a bit and find little in the way of guidance for teachers of the students, mostly along the line of 'alleviating stress' and increasing 'self-esteem'.
I suppose a tactic I would try would involve allowing for choices in how the students address an assignment. As much as feasible I'd try offering the class their choices in forms of presentations of assignments, whether or not they prefer to work in groups or individually.
I've only had one student I was aware of that was 'cutting' but we knew from the psychiatrist that the issues had stemmed from home problems, not school. At school she felt 'safe,' she liked the consistency and rules, so certainly more 'choices' may not have been the way to go with her. I guess bottom line, you need to get to know the student and as much background as you're able to get.